Plant foods

ABSTRACT

A process of enhancing plant growth which comprises applying to crop plants, in an amount effective to enhance the yield of the crop by action on the plant metabolism, a compound selected from the group consisting of 1. COMPOUNDS OF FORMULA:   WHEREIN X is selected from the group consisting of oxygen and sulphur; W is selected from the group consisting of C2-C10 alkyl and the 4,6 bisphosphonyl-2-s-triazinyl radical; Y is selected from the group consisting of hydroxy, amino and radical defined for W; and Z is selected from the group consisting of hydroxyl and amino; and 2. NON PHYTOTOXIC SALTS AND ESTERS THEREOF.

United States Patent [19] Harris et al.

1 1 PLANT FOODS [75] Inventors: Frederick John Harris; John Stewart Raitt, both of Edinburgh, Scotland [73] Assignee: Scottish Agriculture Industries Limited, Edinburgh, Scotland [22] Filed: Oct. 30, 1972 [21] Appl. No.: 301,770

Related US. Application Data [62] Division of Ser. No. 807,908, March 17, 1969, Pat.

[30] Foreign Application Priority Data Mar. 28, 1968 Great Britain 14966/68 Apr. 29, 1968 Great Britain 20217/68 [52] US. Cl 71/77, 71/86, 71/87 [51] Int. Cl. AOln 21/02, AOln 9/36 [58] Field of Search 71/86, 77

[56] References Cited UNITED STATES PATENTS 3,338,701 8/1967 Weil 71/86 3,515,537 6/1970 Weil et a1. 71/86 3,626,037 12/1971 Randall 71/86 3,713,805 l/1973 Randall et a1 71/86 4/1973 Randall et a1 71/86 [451 Nov. 19, 1974 Primary Examiner-James 0. Thomas, J r. Attorney, Agent, or Firm-Cushman, Darby & Cushman 1 [5 7] ABSTRACT A process of enhancing plant growth which comprises applying to crop plants, in an amount effective to enhance the yield of the crop by action on the plant metabolism, a compound selected from the group consisting of 1. compounds of formula:

wherein X is selected from the group consisting of oxygen and sulphur; W is selected from the group consisting of C -C alkyl and the 4,6 bisphosphonyl-2-s triazinyl radical; Y is selected from the group consisting of hydroxy, amino and radical defined for W; and Z is selected from the group consisting of hydroxyl and amino; and

2. non phytotoxic salts and esters thereof.

15 Claims, No Drawings PLANT rooms This is a division, of application Ser. No. 807,908, filed Mar. 17, 1969, now US. Pat. No. 3,733,192.

This invention relates to compounds and compositions for use in agriculture and horticulture by means of which the growth of plants may be controlled.

The usual method of enhancing the yield of a crop is to treat the medium in which the crop is grown with fertilisers. The efficiency of utilisation of fertilisers, however, depends upon their availability coinciding with the time when the crop requires them.

Another method of enhancing the yield is to alter the environmental conditions under which the crops are grown.

The rate of growth of plants may also be controlled to effect a reduction, which may be partial or complete, in the growth of the plants.

We have now discovered that by the use of the compounds hereinafter defined we are able, by selecting the appropriate application rate to affect the growth of plants and thereby:

a. increase the useful yield of plants as regards their quantity and/or composition of the economically important parts of the plants and/or b. increase the uptake of nitrogen by the crop,

thereby increasing the utilisation of the added fertiliser nitrogen and/or increase the percentage nitrogen in the economically important part of the plant and hence its protein content.

c. to suppress the growth of plants.

According to the present invention a method of regulating the growth of plants is provided which comprises treating the plants, seeds or the medium in which they are grown with a compound, a molecule of which includes the structural unit in which P is a phosphorus atom, W is an unsubstituted or substituted saturated or unsaturated aliphatic group containing 1-20 (preferably 2 10) carbon atoms or an unsubstituted or substituted aromatic (e.g., phenyl or naphthyl) or heterocyclic nucleus linked to the phos phorus atom either directly or through a chain of 1-7 (preferably l-3) carbon atoms of an unsubstituted or substituted aliphatic group, X is an oxygen or sulphur atom, and Y and Z, which may be the same or different, each comprises an oxygen or nitrogen atom, a carbon atom which is part of an unsubstituted or substituted aromatic (e.g., phenyl or naphthyl) or heterocyclic group. a carbon atom which is part of a chain of 1*7 (preferably l-3) aliphatic carbon atoms attached to an unsubstituted or substituted aromatic or heterocyclic nucleus, a carbon atom which is part of an unsubstituted or substituted aliphatic group, or, in the case where X is oxygen, a sulphur atom. When Y or Z comprises an oxygen or nitrogen atom the valencies of such atom which are not linked to the phosphorus atom are preferably satisfied by hydrogen, alkali metal, alkaline earth metal atoms or aliphatic or aromatic groups; and when Y and Z comprise a sulphur atom the valencies of such atom which are not linked to the phosphorus atom are preferably satisfied by hydrogen atoms or aliphatic or aromatic groups.

Where W is a substituted aromatic, heterocyclic, or alkylene group, the substituent groups may conveniently comprise a phosphorus atom or atoms and comprise the configuration in which X Y and Z are groups as hereinbefore de fined for X, Y and Z respectively.

It will be realised that the response of plants to a fixed rate of application will vary from one compound to another and from one type of plant to another and that the responses of a particular plant to varying applica tions of the same compound will also vary. It will be further realised that whereas an amount of a compound when applied within certain limits to a plant may produce a certain effect, for example a favourable increase in yield, the same compound when applied in a different amount may produce a different result, for example a higher concentration may produce a retardation of growth, and a still higher concentration may produce a herbicidal effect.

In general, it is expected that a compound of the invention would be applied either as a means of enhancing the useful yield of crops or to achieve a herbicical effect.

We have found, however, that a group of the compounds of the invention is particularly favourable for enhancing the useful yield and/or the quality of crops.

For the purpose of enhancing yields of plants W is preferably a substituted or unsubstituted aliphatic group of ll0 (preferably 2-10) carbon atoms, a substituted or unsubstituted phenyl or naphthyl nucleus linked either directly or through a chain of 1-7 (prefer ably l3) saturated aliphatic carbon atoms to a phosphorus atom, X is oxygen and Y and Z comprises oxygen, nitrogen or a carbon atom which is part of a substituted of unsubstituted aliphatic group of l-l 0 (preferably 2-10) carbon atoms. The remaining valencies of Y and Z are preferably satisfied by hydrogen, alkali metal, alkaline earth metal atoms, aliphatic or aromatic groups.

Accordingly, the invention further provides a method of enhancing the growth of plants which comprises treating the plants, seeds or medium inwhich they are grown with a compound, a molecule of which includes the structural unit in which P is a phosphorus atom, O is an oxygen atom, W is a substituted or unsubstituted aliphatic group of 1-10 (preferably 2-10) carbon atoms, an unsubstituted or substituted aromatic (e.g., phenyl or naphthyl) nucleus linked either directly or through a chain of l-7 (preferably l-3) aliphatic carbon atoms to the phosphorus atom, and Y andZ which may be the same or different, each comprises an oxygen or nitrogen atom or a substituted or unsubstituted aliphatic group of l] (preferably 2-l0) carbon atoms. The remaining valencies of Y and Z which are not linked to the phosphorus atom are preferably satisfied by hydrogen, alkali metal, alkaline earth metal atoms, aliphatic or aromatic groups.

As examples of compounds of the invention the following may be instanced:

Chemical name Formula Phenyl phosphonic diamide O CaH-'NHZ 111. Mono-sodium phenyl 0 phosphate.

C uH P-O Na Sodium phenyl phosphonamidata 0 C uH5-1 -0 Na ILTIIz Phcnyl thiophosphonic diamide S CaH5-i NH2 I IH2 Phenyl phosphonic acid O CaH5l OH p-Chloro phenyl phosphonic acid. 0

ClCOH4-IOH p-Tolyl phosphonic acid O CH C H4 I OH Mono-calcium phenyl phosphonate.

C @115- '1' O C a Naphthyl phosphonic acid C II i OI-I p-Nitro phenyl phosphonic acid- O NOzC@II -'i 0H 2,4-dichlor0 phenyl phosphonic acid. .H

C]zCaII3l--OII Mono-calcium p-chlcro phenyl phosphoi'iatc. moflm lll o Ca 2,4 ,5-tricl1lor0 phony] phos- O phonic acid. ChC0H2 lll on Bis-naphthyl phosphlnic acid. 0

CmI[ i -0II Urolh Bls-u-oetyl phosphlnlc neld 0 nC ll i -OI[ llUgIIn lllsm-mnyi phosphlnlc acid 0 I l!()5II11-l -OI'I Continued Chemical name Formula l5 fl-Naphthyl methane phosphonic acid.

Iriphenyl phosphine oxide Bis-phenyl phosphino thioyl acetic acid.

Mono-calcium benzyl phos- O phonate. ll

Ethyl ester of 2,4,6-triazine triphosphonic acid.

B;Ch1oroethyl phenyl phosphinic O acld' oiomom-i-on (M1, Mono-calcium 3-pheny1 propyl Bis-(fl-ehloroethyl) phosphinic acid.

The compounds may be applied to the seeds, plants or growth medium either without a diluent or in admixture witha suitable diluent. Such diluent may be solid, liquid or slurry.

When used without a diluent they are conveniently applied to the growth medium, or to the seeds prior to sowing. When applied to plants prior to planting out, a compound of the invention may be applied in admix-- ture with a diluent to the roots of the plant.

Examples of solid diluents which may be used are china clay, Kieselguhr, diatomite, bentonite, talc or gypsum. The solid diluent may also comprise fertiliser materials.

In one embodiment of the invention the compounds are incorporated with fertiliser ingredients into, for example a compound fertiliser. Examples of suitable fertiliser ingredients are ammonium phosphate, ammonium sulphate, ammonium nitrate, superphosphates, potas sium chloride, potassium sulphate or mixtures thereof. The CP bond in the compounds is relatively stable, so that the compounds are compatible with most fertiliser salts. If desired, the fertiliser incorporating the LII compound may be granular, pelleted or powdered. Preferably it is granular. The fertiliser may then be applied to the medium in close proximity to the seed by known fertiliser placement techniques.

When applied to seeds the compounds may be applied in admixture with a diluent which may be solid, or fluid. Examples of suitable solid diluents are those instanced above. The liquid may be, for example a surfactant, or non-toxic oil or solvent. As another example of a suitable diluent may be instanced petroleum jelly.

For application to growing plants the compounds are preferably applied in the form of a solution, suspension or emulsion, in admixture with a liquid diluent. When used with a liquid diluent surface active agents may be incorporated.

Examples of liquid diluents which may be used are water, dioxan, alcohols such as for instance ethyl alcohol, methyl alcohol, isopropanol, 2-ethoxyethanol, amyl alcohol and ketones such as for instance acetone or any suitable mixture of such diluents. It will be recognised that the use of liquid diluents other than water will necessitate experiment to determine the quantity of diluent which may safely be used for particular applications. Suitable surface active agents may be selected from known anionic, cationic and non-ionic surface active agents. Lissapol (Regd. Trade Mark) is a very suitable surface active agent for the purpose.

If desired, fertiliser salts, for example such as have already been mentioned, may be dissolved or suspended in the liquid.

In one embodiment of the invention the compounds are applied in admixture with a weed killer which does not have an adverse effect on the growing crop.

In a further embodiment compounds of the invention are applied in admixture with one another to the plants, seeds or the medium in which they are grown.

Thus, according to thepresent invention, there are provided plant growing regulating compositions comprising an effective amount of at least one compound as hereinbefore defined in admixture with a diluent, surfactant, fertiliser or weedkiller.

Also according to the invention there are provided seeds of potentially improved growth characteristics comprising seeds treated with at least one compound as hereinbefore defined which is capable of enhancing the useful yield of plants.

In some cases seeds from treated plants, from plants grown from treated seeds or from plants grown in a treated medium, in each case the treatment being in accordance with the invention may be found to have improved growth characteristics.

Compounds of the invention have been applied to monocotyledonous plants and dicotyledonous plants and have been found to enhance the growth and quality in both when applied at the correct rate.

We have found that when a compound of the invention, for example bis-n-octyl phosphinic acid, was applied to some monocotyledons, for example barley, oats, maize or rice, as a 0.5 percent w/v foliar spray at the two leaf stage a band of approximately one-half inch wide, where much of the tissue had senesced, formed across the leaf near to the base of the leaf. It would appear, however, that the conducting tissue remainded functional since the leaf remained green on either side of the senescent band. In addition the tip of r the third leaf was withered but the subsequent growth had normal appearance.

When this compound was applied to a matured second leaf of a maize plant,care being taken to avoid the solution coming into contact with the growing point of the plant, the subsequent third leaf was produced with a band of senescent tissue as described above.

When an immature third leaf was so treated the band of senescence appeared on the third leaf and the expected withering at the tip of the fourth leaf. This indicates that a compound of the invention may be translocated within the plant from the point of application to a point of cell growth.

When applied to dicotyledonous plants, for example radish and turnip, as an 0.5 percent w/v foliar spray chlorosis of the leaf occurred within 48 hours and over a period of a week the affected leaves died. The plants remained alive, producing new leaves, but the total crop growth was reduced.

The solubility of the compounds of the invention varies. In general, it is found that phosphonic acid derivatives are more soluble in water than phosphinic acid derivatives. However, solubility of the phosphonic acid derivatives within the scope of the invention varies. Thus, phenyl phosphonic acid and its diamide are soluble in water, whereas its calcium salt is only sparingly soluble.

When a compound of the invention is sparingly soluble in water and it is desired to apply it as a foliar spray, it may be emulsified or it may be applied in an organic solvent in which it is more readily soluble.

In certain cases a sparingly soluble compound of the invention may be solubilised by dissolving it in a dilute solution of alkali (for example sodium hydroxide) and then carefully adding dilute acid, for example hydrochloric acid, to neutralise excess alkali without causing precipitation. On the other hand, an insoluble calcium salt of one of the compounds of the invention may be solubilised by dissolving in dilute acid and readjusting the pH of the solution by the addition of dilute alkali, for example sodium hydroxide.

Alternatively the compound may be brought into suspension by the use of suitable emulsifying agents and applied in that form.

It will be realised that each compound must be tested individually in order to arrive at the best means of application and to determine the correct amount of compound to be applied to achieve a desired result with a particular plant.

When admixed with a growth medium the characteristics, for example pH of such medium must be taken into account.

When applied to a growth medium the compounds may conveniently be added to such an extent that the growth medium contains 2.5-500 p.p.m. (preferably 5-350 ppm.) by weight of active compound.

When applied as a foliar spray the compounds may conveniently be applied at rates of from 0.0l-20 lb./acre of active compound in order to effect a herbicidal or retarding action on plants. However, for the purposes of enhancing the growth and useful yield of plants, the compounds may conveniently be applied at rates of 0.0l-l0 lb./acre (preferably 0.057.5 lb./acre) of active compound. y

It will be appreciated that compounds of the invention may be admixed with a suitable solid or liquid dilu ent in any desired proportion, for application to the plants, seeds or media in which they are grown so long as the proportion used enables the compound to be applied at the desired rate without unduly high local concentrations of compound being formed when applied. In this respect, a foliar spray would conveniently contain from 0.05 percent w/v to percent w/v of active compound.

Preliminary tests with chickens on the feeding value of grain produced from seed or plants treated with a compound of the invention have indicated that there is no deleterious effect resulting from their use.

The following examples illustrate the effect of com pounds of the invention on the growth of plants.

In all the examples, unless otherwise stated, the results are expressed on a dry matter basis. The results were also supplied with 120 p.p.m. of nitrogen in the. form of ammonium nitrate, 200 p.p.m. of P 0 in the form of dicalcium phosphate. 150 p.p.m. of K 0 in the form of potassium sulphate, 100 p.p.m. magnesium sulphate and 50 p.p.m. NaCl. 50 seeds of YMER barley were sown in each pot. Soon after emergence of the young plants (at one and a half leaf stage) the plants were thinned to plants/pot. During growth the pots were kept in a greenhouse under natural lighting conditions, no supplementary lighting being supplied. Heating to maintain a minimum night temperature of 55F was supplied as necessary.

Control experiments similar to the above, but omitting the compound of, the invention, were carried out under the same conditions. The results were as follows:

Compound Grain Yield increase over control Nitrogen Uptake increase over control 7r 2.4 dichloro phenyl phosphonic acid mono-calcium p-chlorophcnyl phosphate 2.4.5 trichlorophenyl phosphonic acid Phenyl phosphonic acid Bis naphthyl phosphinic acid Bis-n-octyl phosphinic acid Increases were obtained in the grainlstraw ratio of plants from pots treated with the compounds, when compared with the control tests.

EXAMPLE 2 In this example which further illustrates the enhancement of yields obtained by use of compounds of the invention, the conditions of test were similar to those of the previous example except that the rate of application of the active ingredient was 25 p.p.m./pot. The crop was barley.

Compound Grain Yield increase over control 7r Nitrogen Uptake increase over control 7:

3.4 dichlorophenyl phosphonic acid Mono-calcium benzyl phosphonate 20 Mono calcium phenyl phosphonate 2.4.5 trichlorophenyl phosphonic acid cally useful part of the plant, this increased nitrogen is not due to nitrate or nitrate content.

EXAMPLE 1 In this example compounds according to the invention were added at the rate of 100 p.p.m. of compound/pot of growth medium which consisted of 21 lb. of a mixture of 2 parts of sand and 1 part of soil. The pH of this mixture was approximately 6.0. The pots Increases were obtained in the grain/straw ratio of plants from pots treated with the compounds, when compared with the control tests.

EXAMPLE 3 In this example the conditions of test were as in Example 1 except that the rate of application was 5 p.p.m.

of active ingredient per pot. Again the enhancement of yield is demonstrated on barley.

Compound Grain Yield Nitrogen Uptake increase increase over control over control Bis phenyl thiophosphinic acid 7 17 a naphthyl methane phosphonic acid Mono-calcium phenyl phosphonate Mono-calcium p-chlorophenyl phosphate Mono-calcium benzyl phosphonate 3-chlorophenyl phosphonic acid 8 2.4.5 trichlorophenyl phosphonic acid Bis-n-octyl phosphinic acid EXAMPLE 4 7 EXAMPLE 7 The effect on growth enhancement of application of This example illustrates the use of a compound of the the compounds of the invention at various rates of adinvention as a foliar spray under field conditions.

dition is demonstrated by the following tests carried out 5 Trail plots were sown with barley (variety YMER).

on barley. The fertiliser application was made at the rate of 3 Compound Rate of addition 7: increase in Grain p.p.m./pot Yield overcontrol 2,4 dichlorophenyl phosphonic acid 5 25 3 l()() l2 Phenyl phosphonic acid l 25 I S 100 14 EXAMP LE 5 The suppressant action of compounds according to cwts/acre of a compound fertiliser containing perthe invention is illustrated by this example, from which 20 cent nitrogen, 14% P 0 and 14% K 0. A compound of it will be seen that by varying the amount of active inthe invention, phenyl phosphonic acid, was applied to gredient applied to the medium the yield may be supplots as a foliar spray of concentration 0.5 percent w/v pressed or enhanced. The conditions of test were as in at rates of 1 lb./acre and /2 lbJaCre at the three leaf Example 1. The crop was barley. stage of growth. The results were as follows:

Compound Rate of addition 7: increase in Grain p.p.m./pot Yield over control Bis p'chlorophenyl phosphinic acid 5 +5 -9 100 -24 Bis phenyl thio phosphinic acid 5 +7 25 -5 100 9 B naphthyl methane phosphonic acid 2.2 +66 106 17 Mono-calcium p-chlorophenyl phosphonate 5 +12 25 +4 100 3 Bis'n-amyI phosphinic acid 5 +2! 25 100 -7 Phenyl phosphonic diamide 75 +l5 150 -13 300 -70 This example illustrates that the amount of a com- Crop B a ey pound of the invention to be added to the medium to achieve a desired effect varies from compound to coms Of application 1 Grain Yield increase over 20 7 pound and that testing is necessary to determine the comm, optimum amount of a compond to be used to obtain the Nitrogen uptake increase 3 9 desired effect comm] EXAMPLE 6 In Example 5 the beneficial effect of phenyl phos- EXAMPLE 8 phonic diamide was demonstrated at a level of 75 A compound of the invention phenyl phosphonic p.p.m. by weight. This experiment was carried out acid was applied as a foliar spray under field conditions under a full nitrogen fertilisation regime. A separate ext0 oat plants at the three leaf stage of growth with fertiperiment in which the same amount of phenyl phOsliser application as in Example 7.

Rate of application Grain Yield Nitrogen Uptake Increase over control increase '7: over control l [b.lacre 2| 27 V2 lbJacre 13 ll phonic diamide was added was carred out with reduced nitrogen level (a quarter of full level) when an increase EXAMPLE 9 in grain yield of 24 percent was obtained. The total ni- Compounds of the invention were added at various trogen uptake was similar as the nitrogen content of the rates to p ts f s il/sand mixture supplied with added grain was maintained. fertiliser ingredients as in Example 1. 12 seeds of radish any addition of a compound of the invention to the medium and under the same environmental conditions.

The fresh root weight yield of the radishes was increased by 14 percent.

EXAMPLE 12 A compound of the invention was added at various rates to pots of soil/sand mixture supplied with added fertilizer ingredients as in Example 1 except that there 10 was no added nitrogen. 20 clover seeds were sown in Compound Rate of application Fresh weight root increased Root p.p.m. increase 7! over Nitrogen Uptake control over control Mono-calcium phenyl 10 29 18 phosphonate Mono-calcium henzyl 10 1() 34 phosphonate Mono-calcium henzyl 5O 8 44 phosphonate EXAMPLE 10 each pot and thinned at a later stage to 10 plants/pot.

In a parallel experiment to that of Example 9 compounds of the invention Bis-n-octyl phosphinic acid Environmental conditions were as in Example 9.

The crop was harvested after 12 weeks.

Compound Rate of application Fresh weight yield Nitrogen Uptake and mono-calcium phenyl phosphonate were added at p.p.m. increase over increase yield control 70 over control '70 Ethyl ester of 2,4,6 100 14 32 triazine triphosphonic acid 25 15 18 35 EXAMPLE 13 various rates to pots of soil/sand medium as in Example 9, and radish were sown, grown and harvested as in that example.

The results illustrate the varying effect which may be obtained on plants by the variation of the rate of application.

Compounds of the invention were added as foliar sprays to clover grown as in Example 12. The application was made as 0.5 percent w/v solution to run of at the six trifoliate leaf stage of growth. The plants were harvested 12 weeks after sowing.

Compound Rate of application Fresh weight p.p.m. root yield increase over control "/1 Mono-calcium phenyl phosphonatc 200 -75 50 15 10 +29 Bis-nctyl phosphinic acid 200 20 O 3 Compound Fresh weight Nitrogen Uptake increased yield increased yield over control Mono-calcium phenyl phosphonate 20 Mono calcium henzyl phosphonate 13 16 Bis-n-octyl phosphinic acid 19 EXAMPLE ll EXAMPLE 14 A compound of the invention, mono-calcium phenyl phosphonate, was applied to a crop of radish as a 0.5

A compound of the invention, phenyl phosphonic acid was admixed with fertiliser ingredients to form a percent w/v foliar spray to run off. The radishes were compound fertiliser having an approximate analysis 20 grown in a soil/sand medium as in Example 9 without percent nitrogen, 14% P 0 14% K 0 and having incorporated therein 2.5 percent by weight of the compound. The so treated fertiliser was applied to prepared test plots at the rate of 3 cwt./acre. Plots were seeded with Italian ryegrass and Perennial ryegrass. Control plots were laid down at the same time.

Inspection of the plots after 16 weeks showed that the growth of grass was markedly increased in the plots treated with phenyl phosphonic acid.

In pot experiments using ryegrass as the test crop a compound according to the invention, phenyl phosphonic diamide, was incorporated in the growth medium at a rate of 250 ppm. by weight, together with sufficient nutrients to ensure complete growth. Control pots similar in all respects to the test pots but omitting the compound were also prepared and all pots sown EXAMPLE 1? Compounds of the invention were applied, at the rate shown, to p ot s of soil/sand medium. Turnip seeds were sown in the pot and later thinned to three plants/pot. The plants were grown under similar environmental conditions to those of Example 9.

The crops were harvested 12 weeks after sowing.

with the same amount of seed. The yield of grass from pots treated with the compound was reduced by about 10 percent when compared to the control, but the nitrogen uptake by the grass in the treated pots was increased by almost 50 percent.

It has been found that compounds of the invention may, if applied in sufficient quantity, be used to retard the growth of grass. Such application has the additional effect of intensifying the green colour of the grass during the growing season and of enabling this colour to be maintained during the winter months.

EXAMPLE l5 Compounds of the invention were applied at the rates shown to boxes containing 14% lb. of John Innes No. l Compost and having 60 ppm. by weight of nitrogen as ammonium nitrate incorporated therein. Lettuce seeds (variety Neptune) were sown in the boxes and the seedlings thinned to two plants/box. The environmental conditions were as in Example 9. The lettuce were harvested 13 weeks after sowing.

A compound of the invention, mono-calcium benzyl phosphonate was applied as a 0.5 percent w/v foliar spray to -run off to turnip plants at the four leaf stage of growth. The turnips were grown as in Example 17.

The crops were harvested 12 weeks after sowing and the treated plants gave a 9 percent increase in dry weight over a control test.

EXAMPLE 19 Ymer barley was grown in pots as in Example 1 ex cept that the environmental conditions were those used in Example 9. The compound of the invention treated, mono-calcium benzyl phosphonate, was admixed with the medium at the application rate of 5 p.p.m. A 16 percent grain yield increase over control and a 19 per cent increased nitrogen uptake over control were obtained.

Compound Rate of application Fresh weight yield Nitrogen Uptake p.p.m. increase over increase yield control 7% over control 7:

Bis-n-octyl phosphinic 250 17 24 acid Bis-n-octyl phosphinic 75 26 42 acid Bis-n-octyl phosphinic 25 21 3 acid Ethyl ester of 2.4.6 25 24 I7 triazinc tri phosphonic acid Mono-calcium phenyl 25 20 29 phosphonate Mono-calcium benzyl 75 53 phosphonate Mono-calcium benzyl 25 21 21 phosphonate EXAMPLE 16 EXAMPLE 20 A compound of the invention, ethyl ester of 2,4,6 tri azine triphosphonic acid, was applied as an 0.5 percent w/v foliar spray to run off to lettuce plants grown in Pots of Ymer barley grown as in Example 19 were foliar sprayed with compounds of the invention. The concentration used was 0.5 percent w/v and the compound was applied at rates equivalent to 0.2 1b., 1 lb. and 6 1b./acre. The results obtained were as follows:

9% P and 12% K 0 was applied. At a later stage of growth when plants were 15 inches high a further dress- Compound Rate Stage of Grain Yicld Nitrogen Uptake IhJacre application increase over increase over control C4 control '71 Mono-calcium henzyl 1 2 leaf 30 23 phosphonate Bis-n-oct v1 phosphinic 0.2 2 leaf 18 2X acid Bis-n-octyl phosphinic 0.2 4 leaf 36 20 acid Bis henzyl thiophosphinic 6 4 leaf 10 acid EXAMPLE 21 mg of 100 lbs/acre of urea (containing 46 percent n1- Compounds according to the invention were added at the rates shown to pots containing a soil/sand medium and an adequate supply of phosphate, potash and minor plant nutrients. The nitrogen addition in the trogen) was applied.

Foliar applications of compounds of the invention at the four leaf stage of growth were made to the test plots at various rates with the following results. Results are the mean of six replicate tests.

Compound Rate of Grain Yield Ear/Plant Nitrogen Uptake application increase over ratio increase over 1hs./acre control control 7:

Benzyl phosphonic 0.25 4.0 1.03 -4 acid 1.0 10.0 1.03 12 4.0 18.0 0.99 18 Phenyl phosphonic 0.25 11.0 1.07 1

acid Control 0.91

growth medium was at a level of 45 p.p.m. nitrogen, if EXAMPLE 23 necessary being supplied in the form of ammonium nitrate. In one instance the nitrogen level in the growth medium was 90 p.p.m. nitrogen. The crop tested was oats.

Soya beans (variety Masterpiece) were grown in test plots under normal field conditions in rows 3 ft. apart. The seeds were sown at the rate of lbs/acre. Fertiliser dressings were applied as outlined in Example 22.

Compound Rate of addition Grain Yield Nitrogen Uptake p.p.m. increase over increase over control 2 control '14 Phenyl phosphonic diamide 250 23 63 Phenyl phosphonic diamide 250 20 64 p.p.m. nitrogen) p-nitro phenyl phosphonic acid 7 5 Benzyl phosphonic acid 50 12 13 Phenyl thiophosphonic acid 250 30 46 EXAMPLE 22 A compound of the invention was applied to the Maize (variety SA 200) was grown in test plots under normal field conditions in rows 3 ft. apart with 1 ft. be tween plants. At planting a fertiliser dressing of 3 cwts./acre of a fertiliser containing 6 percent nitrogen,

seeds in admixture with separated milk to obtain adherence of the compound to the seed.

Results quoted are the mean of six replicate tests and are compared to control plots which were grown with untreated seed.

Compound Rate of application Fresh Weight Yield Nitrogen Uptake to seed (94 w/v) increase over increase over control 7: control l1 Calcium henzyl 5 8 8 phosphonatc EXAMPLE 24 ronmental conditions of Example 9 for a further 4 '0 weeks after which time the crop was harvested. An increase in dry weight yield of 14 percent was obtained. The pH of the medium in this example was 5.8.

EXAMPLE 25 Barley plants were grown in pots under the conditions of Example 1 and under environmental conditions of Example 1.

Compounds of the invention were applied to the 20 growing plants as foliar sprays at the two leaf stage of growth.

Compound Rate of addition Increase Grain invention in admixture with fertiliser ingredients under field conditions.

A granular concentrated complete fertiliser was prepared incorporating 2.5 percent phenyl phosphonic acid. The fertiliser formulation was such as would have given an analysis of 20 percent nitrogen, 14 percent total P and 14% K 0 if no phenyl phosphonic acid had been added. It was considered that the amount of dilution brought about by the addition of the phenyl phosphonic acid was negligible for the purposes of the test.

. The fertiliser was applied to prepared plots at the rate of 3 cwts./acre by placement in the soil adjacent to the seed at the time of sowing. The crop used was barley (variety YMER) and a control test was carried out at the same time.

Grain Yield increase over control 7 Nitrogen Uptake increase over control lncreased (lbs/acre) Yield over Nitrogen Uptake control A over control 7:

Mono-calcium henzyl phosphonate l 30 23 Ethyl ester of 2.4.6 triazine 2% l0 9 triphosphonic acid Bis Bchloroethyl) phosphinic 0.5 5

acid Phenyl Bchloroethyl phosphinic 2% l2 5 acid Mono-calcium 3-phenyl propyl 2% 9 5 phosphonate EXAMPLE 26 Barley (variety Olli) was grown in pots as in Example 1 and under the environmental conditions of Example 9. Compounds of the invention were mixed into the medium at the rates shown. The crops were harvested after 14 weeks and compared with controls grown under the same conditions.

Thus, although the fertiliser application was marginally less than the fertiliser applied to the control, there was a substantial nitrogen uptake increase.

EXAMPLE 28 Some of the compounds of the invention exhibit a Compound Rate of addition Grain Yield Nitrogen Uptake p.p.m. increase over increase over control control 70 Mono-calcium phenyl 50 21 phosphonate Behloroethyl phenyl 50 23 21 phosphinic acid 10 19 13 Bis ethyl amino phenyl 5O 14 12 phosphonic acid Diethyl ester of 2,4,6 50 8 l3 triazine triphosphonic acid EXAMPLE 27 strong suppressant action as illustrated by the following This example illustrates the use of a compound of the tests carried out on barley underthe conditions of Example 1.

Compound Rate of addition "/r increase in p.p.m. yield over control Triphenyl phosphinc oxide 5 l4 25 100 82 p-chlomhcnzyl phosphonic acid 5 2 25 7 100 -79 Bis phenyl phosphinothioyl acetic acid 5 -4 EXAMPLE 29 In order to demonstrate that the compounds of the invention are not deleterious to germination when applied as a seed dressing, 2 percent by weight of phenyl phosphonic diamide was applied with 1.5 percent by weight of petroleum jelly to oats seeds. Laboratory germination tests showed that there was no diminution in germination with these seeds compared with those coated with 1.5 percent petroleum jelly only or uncoated seeds.

EXAMPLE 30 wherein X is selected from the group consisting of oxygen and sulphur; W is selected from the group consisting of c -C alkyl and the 4,6 bisphosphonyl-Z-striazinyl radical; Y is selected from the group consisting of hydroxy, amino and a radical defined for W; and Z is selected from the group consisting of hydroxyl and amino; and

2. non phytotoxic salts and esters thereof.

2. A process according to claim 1 wherein the crop plants are cereals.

3. A process according to claim 1 wherein the compound is selected from the group consisting of compounds of the formula where W is a C C, alkyl, Y has a value as indicated in claim 1, and the salts and esters thereof.

4. A process according to claim 3 wherein the compound is selected from the group consisting of bis-noctyl phosphinic acid, bis-n-amyl-phosphinic acid, namyl-phosphonic acid and n-octyl-phosphonic acid and salts and esters thereof.

5. A process according to claim 1 wherein the compound is selected from 2,4,6-triazine triphosphonic acid and salts and esters thereof.

6. A process as claimed in claim 1 wherein the compound is applied as a foliar spray at a rate of 0.0ll0 lb per acre.

7-. A process as claimed in claim 6 in which the rate is 0.0l7.5 lb per acre.

8. A process according to claim 1 wherein the compound is applied to crop plants by treating seeds thereof with a seed dressing containing said compound.

9. A process of enhancing plant growth which comprises applying to crop plants, in an amount effective to enhance the nitrogen content thereof by action on the plant metabolism, a compound selected from the group consisting of 1. compounds of formula 11. A process according to claim 9 wherein the compound is selected from the group consisting of compounds of formula wherein W is a C C alkyl and the 2-haloethyl radical, Y has a value as indicated in claim 9, and the salts and esters thereof.

12. A process according to claim 11 wherein the compound is selected from bis-n-octyl phosphinic acid, bis-n-amyl phosphinic acid, n-amyl phosphonic acid and n-octyl phosphonic acid; and salts and esters thereof.

13. A process as claimed in claim 9 wherein the compound is applied as a foliar spray at a rate of 001-10 lb. per acre.

14. A process as claimed in claim 13 in which the rate is 0.0l7.5 lb per acre.

15. A process according to claim 9 wherein the compound is applied to crop plants by treated seeds thereof with a seed dressing containing said compound. 

1. A PROCESS OF ENHANCING PLANT GROWTH WHICH COMPRISES APPLYING TO CROP PLANTS, IN AN AMOUNT EFFECTIVE TO ENHANCE THE YIELD OF THE CROP BY ACTION ON THE PLANT METABOLISM, A COMPOUND SELECTED FROM THE GROUP CONSISTING OF
 1. COMPOUNDS OF FORMULA W-P(=X)(-Y)-Z WHEREIN X IS SELECTED FROM THE GROUP CONSISTING OF OXYGEN AND SULPHUR; W IS SELECTED FROM THE GROUP CONSISTING OF C2-C10 ALKYL AND THE 4,6 BISHPOSPHONYL-2-S-TRIAZINYL RADICAL; Y IS SELECTED FROM THE GROUP CONSISTING OF HYDROXY, AMINO AND A RADICAL DEFINED FOR W; AND Z IS SELECTED FROM THE GROUP CONSISTING OF HYDROXYL AND AMINO; AND
 2. NON PHOTOTOXIC SALTS AND ESTERS THEREOF.
 2. non phytotoxic salts and esters thereof.
 2. A process according to claim 1 wherein the crop plants are cereals.
 2. non-phytotoxic salts and esters thereof.
 3. A process according to claim 1 wherein the compound is selected from the group consisting of compounds of the formula
 4. A process according to claim 3 wherein the compound is selected from the group consisting of bis-n-octyl phosphinic acid, bis-n-amyl-phosphinic acid, n-amyl-phosphonic acid and n-octyl-phosphonic acid and salts and esters thereof.
 5. A process according to claim 1 wherein the compound is selected from 2,4,6-triazine triphosphonic acid and salts and esters thereof.
 6. A process as claimed in claim 1 wherein the compound is applied as a foliar spray at a rate of 0.01-10 lb per acre.
 7. A process as claimed in claim 6 in which the rate is 0.01-7.5 lb per acre.
 8. A process according to claim 1 wherein the compound is applied to crop plants by treating seeds thereof with a seed dressing containing said compound.
 9. A process of enhancing plant growth which comprises applying to crop plants, in An amount effective to enhance the nitrogen content thereof by action on the plant metabolism, a compound selected from the group consisting of
 10. A process according to claim 9 wherein the crop plants are cereals.
 11. A process according to claim 9 wherein the compound is selected from the group consisting of compounds of formula
 12. A process according to claim 11 wherein the compound is selected from bis-n-octyl phosphinic acid, bis-n-amyl phosphinic acid, n-amyl phosphonic acid and n-octyl phosphonic acid; and salts and esters thereof.
 13. A process as claimed in claim 9 wherein the compound is applied as a foliar spray at a rate of 0.01-10 lb. per acre.
 14. A process as claimed in claim 13 in which the rate is 0.01-7.5 lb per acre.
 15. A process according to claim 9 wherein the compound is applied to crop plants by treated seeds thereof with a seed dressing containing said compound. 